I have house built in ’52 on expansive soil. The crawl space soil stays damp year round. I have plastic sheeting on the soil; it is not sealed to the foundation. Standard crawl space vents. There is no insulation under the house.
I was thinking that it would be easiest to insulate and air seal the house with spray foam insulation. I am not sure if that is wise with the amount of moisture that is under the house. Will the SPF collect moisture or allow it to be trapped in the subfloor?
Anyone have any thoughts or experience?
Replies
Closed cell
foam is highly impermeable and will not permit additional moisture through. If there is a lot of moisture in your subfloor or joists, and it can't dry to the top, I would dry it out before foaming it. And I would seal the vapor barrier sheet well at all overlaps and at the perimeter.
You should get ahold of a moisture meter and take some readings in the framing and subfloor materials.
I would use the spray foam insulation as well and definitely dry everything out first. Just make sure if there are any large gaps in the floor boards that the foam will not go through to the other side, could make quite a mess. If you want more information go to http://www.sprayfoamdirect.com/
Insulating Solution
I found a really good article that discusses the various elements of foam insulation. It's a good resource for those that don't understand what it is. You can view it here: http://www.sprayfoaminsulations.net/foam-insulation/
I have found that spray foam is becoming more and more popular as it provides considerable energy cost savings over time.
Thanks. Sounds like a plan.